Linear Predictive Coding attempts to predict a future data value. It would be useful to be able to have a device that detects and corrects errors in both a future and a past data value. The present invention is such a device.
U.S. Pat. No. 4,686,644, entitled “LINEAR PREDICTIVE CODING TECHNIQUE WITH SYMMETRICAL CALCULATION OF Y-AND B-VALUES,” discloses a digital lattice filter that includes a Y-adder and a B-adder. U.S. Pat. No. 4,686,644 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,899,385, entitled “CODE EXCITED LINEAR PREDICTIVE VOCODER,” discloses a device for encoding speech using a code excited linear predictive encoder using a recursive computational unit. U.S. Pat. No. 4,899,385 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,980,916, entitled “METHOD FOR IMPROVING SPEECH QUALITY IN CODE EXCITED LINEAR PREDICTIVE SPEECH CODING,” discloses a method of achieving higher quality speech by reconciling differences between the estimator and the filter of a code excited linear predictive voice coder. U.S. Pat. No. 4,980,916 is hereby incorporated by reference into the specification of the present invention